Quick and dirty A64 clocking guide **UPDATE** X2 OC information!

[theMan]

i dont think you should get hung up on the ram. just use your max cpu at all times, then figure out what to do with the ram from there. you can decide to go for low latency or high bandwidth. i wouldnt go higher than 2.9, you may run into some problems later on with it, and you wont have that much of a benefit. i mean, if you went up to 4 volts im sure you could run ddr550 @ 2-2-2 but that would just be impractical.

 

[edmundoab]

should I then back it down to 2.8V?
i guess I could do that and give another trial test run

oh yea.. seems like 7 loops of memtest86 is alright for 265 x 9 using 5/6
and thats about.. 220 Mhz too after calculation
does using the divider makes it more "stretchable"?

 

[theMan]

it shouldnt, maybe you just got lucky that time. but really, i wouldnt worry about your ram, run it at 150mhz with 1.5-2-2-4 timings. that would beat 250mhz.

 

[edmundoab]

advice taken

 

[Ketchup]

Originally posted by: theman

the latency wont effect the cpu overclock, just the ram. what kind of ram do you have? also, using a divider doesnt hurt performance at all, so go right ahead.

This may be the case on your system, but with my NC, relaxed memory timings are needed to run both the CPU and memory at high speed. If I use a divider, I can run tighter timings, but performance is better for me with loose timings and memory at 255 MHz.

 

[edmundoab]

i haven't got a chance to compare if divider is better or looser timings,
but since bandwidth wins,
ketchup79 gotta be right

 

[theMan]

Originally posted by: ketchup79

Originally posted by: theman

the latency wont effect the cpu overclock, just the ram. what kind of ram do you have? also, using a divider doesnt hurt performance at all, so go right ahead.

This may be the case on your system, but with my NC, relaxed memory timings are needed to run both the CPU and memory at high speed. If I use a divider, I can run tighter timings, but performance is better for me with loose timings and memory at 255 MHz.

yes, relaxed timings will allow faster ram, but if you are just finding max cpu speed, you dont need to worry about latency

 

[edmundoab]

I've finally found a sweet spot for my chip this morning at 262 x 9
RAM definately a limitation at CAS 2.
but I don't mind keeping it at low latency

at least it ran Prime95 stable for over 9 hours @ Vcore 1.550v
at situation like this, even 0.25v made such a difference. I had my Vcore aet 1.525v and it failed prime after only 3 hours..

 

[Norge]

I have one guestion.I dont know what is wrong, but i cant push my Vcore more than 1.45v because my PC crashes. What can be wrong?
My FSB is 274×8.

 

[edmundoab]

hmm, normally more Voltage will give more juice to the CPU, why would it make it crash unless the heat went over the limit,

I see u are using a PC3200 in your rig, what memory divider did u use to get to 274 FSB?

 

[Norge]

i have my memory divider on cpu/10 (333Mhz).But i think that is not the problem because my PC crashes also if i dont overclock it and only increase Vcore of procesor.

 

[theMan]

that sounds like you may have a corrupted bios or something, after it crashes have you tried to do the same thing right afterwards? sometimes that happens to me, and i try again and it works. try flashing the bios to the newest version, or reflash if you already have it.

 

[Ketchup]

Originally posted by: Norge
I have one guestion.I dont know what is wrong, but i cant push my Vcore more than 1.45v because my PC crashes. What can be wrong?
My FSB is 274×8.

I have never heard of your power supply. Where did you get it?

 

[imported_Booky]

Perfectly starightforward guide. kewl. Zebo, as the author, do you allow me to translate it to hebrew and post it on a big hardware israeli forum? I would never do it without premmision.
The forum site is HWZone.co.il. There are alot of noob OCers and this guide would be D thing for them.

 

[Norge]

you mean LC Power 550W?
I have the newest bios update revision 1008 and still crashing.

 

[Ketchup]

Originally posted by: Norge
you mean LC Power 550W?
I have the newest bios update revision 1008 and still crashing.

Yeah, that's the one. Where did you get it?

 

[yanman]

Great guide, it took me a while of sifting through bits and peices before I came across this one, and its perfect! So concise!

In my excitement to run through the steps thought, I got a bit carried away and forgot to keep an eye on my hypertransport speed I set the htt multiplier to 4x and started at 250, so that's fine, but then i forgot to change it down to 3x as I went to htt of 275, then 300, then 325 :/ 325 posted so i went to 350 and no post... okay i thought, this is where i drop back... er.. oops... httt multiplier is still at 4x!! so i hastily clocked it back to 3x and 250 fsb but from then on windows would just reboot before reaching the title screen. I tried a repair install with the cd but it BSODd... so am reinstalling now

Please someone tell me I haven't screwed my venice ( Exactly how bad IS going over 1000 hypertransport? i actually booted into windows at 4x325 eeyikes

 

[theMan]

wait, it bsod'd at with 250htt*3? or when you had it higher? a make sure you arent overclocking anything when you reinstall. set everything back to stock. that stinks.

 

[Ketchup]

Originally posted by: yanman
Great guide, it took me a while of sifting through bits and peices before I came across this one, and its perfect! So concise!

In my excitement to run through the steps thought, I got a bit carried away and forgot to keep an eye on my hypertransport speed I set the htt multiplier to 4x and started at 250, so that's fine, but then i forgot to change it down to 3x as I went to htt of 275, then 300, then 325 :/ 325 posted so i went to 350 and no post... okay i thought, this is where i drop back... er.. oops... httt multiplier is still at 4x!! so i hastily clocked it back to 3x and 250 fsb but from then on windows would just reboot before reaching the title screen. I tried a repair install with the cd but it BSODd... so am reinstalling now

Please someone tell me I haven't screwed my venice ( Exactly how bad IS going over 1000 hypertransport? i actually booted into windows at 4x325 eeyikes

Peobably didn't hurt anything. I think you most likely just currupted your windows install. Install windows again from scratch, and you should be fine. Way to go on your overclock BTW.

 

[yanman]

phew.. system is okay now after a clean install of XP

This time I started again, being *careful*

I reached a HTT of 350x3 but didnt wnat to go any further over 1050 so I tried 2x400 but no cigar.

I started failing prime at 315x9 (3xHTT) - 2835Mhz, so following the guide, my max should be 9x2700. I plugged the values into Gogar's calculator (nice work man!) and the best combo I can seee is:

HTT = 337, CPU = 8x (2696), Memory = 3:5 (125) - 207Mhz, Hypertransport = 3x337 (1011)

The 350HTT combo looks good (2625) but would mean running memory at 175.. not sure whats more important.

(My memory cant do more than 210 i tihnk)

 

[yanman]

update

the max values i found (after 5% back down)
FSB/HTT: 366
CPU: 2700
RAM: 237

but i'm limited to /3 dividers (or multiples of 33) with my A8N-SLI (non-deluxe) so I've gone with this final setup:
337 x 8 - 2696Mhz (3xHTT) - 1011Mhz hypertransport @ 1.5V
ram at 225mhz (2:3) 2.5-3-4-7 1T @ 2.9V

My ram has SPD of 3-3-3-8 at 200 so I'm happy it handled being so out of spec. I had 2.9V in it, following the guides recommendation that this was safe for any DIMM.

So far I've primed it for 4 hours straight and it's fine, plus I was using it all last night playing farcry and reinstalling my apps. I've got it priming at the moment while I'm at work, so hopefully it should all be fine when I get home.

Temperatures have never gone above 44C even after the 4 hour prime, although it is the start of winter here and f**king cold!!!!

w00t, venice cores rock!!

 

[theMan]

nice job! enjoy your new fx-55!

 

[The Godfather]

whats htt? is it the same thing as your native fsb? also, if i have my native fsb at 200Mhz what would happen if i just kept bringing up my multiplier would it fry at a lower speed? i dont really understand the memory section could you explain a little more? how high could i get the amd 64 3000+ with an abit nf8-v and have it absolutely stable? is 3Ghz to optimistic, right now its 2.01Ghz at 200Mhz*~10

 

[theMan]

htt is similar to the fsb. the cpu speed is calculated by htt*multi. you cannot increase your multi past 9. it is locked. 3000mhz is usually only possible with rediculous phase change cooling. i dont think you can pass 2700, depending on what core you have. make sure to reduce your htt to 3x when you increase the fsb. just follow the guide. dont try to jump to any conclusions about your max oc. its different on all systems.

 

[The Godfather]

my multi is at 10 now???